To act in a manner that indicates a hand is weaker than it actually is; hiding the strength of a hand to encourage opponents to bet more aggressively.

Golf - Rule 6-7

6-7. UNDUE DELAY; SLOW PLAY: The player must play without undue delay and in accordance with any pace of play guidelines that the Committee may establish. Between completion of a hole and playing from the next teeing ground, the player must not unduly delay play.

PENALTY FOR BREACH OF RULE 6-7: Match play – Loss of hole; Stroke play – Two strokes. For subsequent offense – Disqualification.